Rene boiin



NITE STATES ATENT OFFICE.

RENE BOIIN, OI! LUD\YIGSIIAFEN-ON-TIIE-RlIINE, BAI'ARIA, ASSIGI'OR TO THE BADISCIIE ANIIIIN AND SODA FABRIK, OF MANNIIEIM, GERMANY.

ALIZARINE INDIGO-BLUE.

SPECIFICATION forming part of Letters Patent No; 399,482, dated March 12, 1889.

Application filed October 31, 1888. Serial No. 289,678. t$peeimens.l

To all whom it may concern.-

of Switzerland, residing at Ludwigshaten-onthe-Rhine, in the Kingdom of Bavaria and 5 Enlpll' of Germany, have invented new and useful Improvements in the Manufacture of Alizarine Indigo-Blue, of which the following is a specification.

My invention relates to the manufacture of IO an improved d ye-stuff or coloring-matterproduced bythe action of concentrated sulphuric acid upon alizarinegreen at a temperature of about 200 centigrade.

In carrying out my invention I mayemploy alizarine-green. either in its finished mercantile condition or in the state of its solution in sulphuric acidsuch results from the successive treatment of alizarine-blue with sulphuric anhydride and concentrated sul- 2o phuric acid in the process of preparing alizarine-green described in my former application for Letters Patent, filed October 18, 1888, Serial No. 288,429.

The following an example of the manner in which alizarinegreen may be converted into alizarine imligo-blne: About ten parts, by weight, of dry and :[inely-powdered alizarine-green are intimately mixed with or dissolved in about two hundred parts,by weight, of concentrated or rectified sulphuric acid of about ISIS specific gravity, and the mixture or solution thus prepared is then under constant agitation heated to 21.0 eentigrade, until it has assumed a pure indigo-blue color, which point will generally be arrived at: j'ter about five hours heating. The result of the operation. is then carefully poured into water, and the precipitate thus formed is collected upon a filter, washed, and pressed, and may 40 afterward be dried or may be used in the state of a paste.

Alizari ne indigo-blue prepared as above described is insoluble in wai er even at theboiling-heat. It forms blue saline compounds upon treatment with caustic or carbonated i3 alkalies. These alkaline salts are quite insoluble in caustic-allmline solutions. It dissolves with a bright indigo-blue color in concentrated sulphuric acid, and may thus be readily distinguished from alizarinegreen, the solution of which in the said solvent is characterized by its red color. It combines with the bisulphites ot' potash, soda, or ammonia, thus producing compounds soluble in water and capable of being employed in dyeing and print-in in a similar manner as analogous bisulphite compounds of alizarine-blue.

Alizarine indigo blue produces upon chrome-mordanted wool shades which are similar to those produced by indigo-blue. 6o

hat I claim as new, and desire to secure by Letters Patent, is

As a new product, the coloring-matter or dye-stuff (alizarine indigo-blue) hereinbefore ribed, and having the following characics: It is insoluble in water even at the boiling-heat; it forms blue saline compounds upon treatment with caustic or carbonated alkalies, which compounds are quite insoluble in caustic-alkaline solutions; it dissolves with a brightindigo-blue colorin concentrated sulphuric acid; it combines with the bisulphites of potash, soda, or ammonia, thus producing compounds soluble in water and capable of being employed in dyeing and printing; upon chrome-mordan1ed wool it produces shades similar to those produced by indigo-blue.

In testimony whereof I havehereunto set my hand in the presence of two subscribing wit- 8o nesses.

R. BOIIN.

\Vitnesses:

'II. FURMANN, Ilnnn; IIANTZ. 

